Regimes identification of the viscous flow past an elliptic cylinder for Reynolds number up to 10000

• Published in: Communications in nonlinear science & numerical simulation Vol. 102; p. 105902
• Main Authors: Durante, D., Giannopoulou, O., Colagrossi, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2021; Elsevier Science Ltd
• Subjects: Amplitude modulation; Angle of attack; Aspect ratio; Elliptical cylinders; Flow past an elliptical cylinder; Fluid flow; Fluid mechanics; Fourier transforms; Hydrodynamics; Incompressible flow; Reynolds number; Viscous flow; Viscous flows; Vortex particle method; Vorticity; Vortex particle method; Viscous flows; Flow past an elliptical cylinder
• ISSN: 1007-5704; 1878-7274
• DOI: 10.1016/j.cnsns.2021.105902

•The viscous flow past 2D elliptic cylinder is investigated.•Incidence of ellipse and Reynolds number are varied for two aspect ratios.•Different regimes are identified: steady, periodic and chaotic.•The lift force is considered and analyzed with typical tools of dynamical systems.•Period-doubling, period-tripling and period-quadrupling bifurcations were identified. In the present paper, the study of different regimes arising from the incompressible planar viscous flow past an elliptical cylinder is presented. In order to highlight the effect of the different parameters on the onset of the regimes, two different aspect ratios, 0.10 and 0.40, are considered and the angles of attack span from 0∘ to 90∘, while the Reynolds number is gradually increased from 100 to 10000. The analyses are focused on the lift force acting on the ellipse in order to identify the regime, with a consideration on the vorticity field patterns of the wake fields. The different regimes are investigated and the chaotic behaviour is established through different tools such as the Fourier spectra, phase maps and Poincaré sections. The investigation of the periodic regimes revealed several possible conditions in terms of lift time signal: monochromatic, non-monochromatic and sub-harmonic regimes. In addition, a quasi-periodic time behaviour with an underlying irregular amplitude modulation was also found among the test matrices performed. Increasing the Reynolds number the periodic regimes are lost, giving the place to chaotic behaviour. The numerical solutions are obtained through a vortex particle method called Diffused Vortex Hydrodynamics (DVH). Long time simulations have been carried out in order to guarantee the correct identification of the attained regime.